Switchgears for the distribution of electric power are well known. In a three-phase system such a switchgear may comprise one or more functional units in a gas filled compartment, each one comprising a grounded enclosure, three bushings connected to three external power cables (one for each phase), three conductors arranged inside the enclosure and in one end connected to a respective bushing and in the opposite end connected to a respective switching device. Each switching device may comprise a breaker (such as a load breaker or vacuum interrupter), possibly in series with a so-called selector switch and connected to a bus bar. It is one bus bar for each phase. Each bus bar extends through all functional units comprised by the gas filled compartment.
In order to reduce or minimize the risk of having electric discharges and short circuits between the voltage-carrying components themselves, i.e. the different phases, or between the voltage-components and the surrounding walls of the encapsulation, the components are positioned at certain minimum distances from each other and from the surrounding walls. The compartment may be filled with a suitable electrically insulating gas, such as SF6.
According to a switchgear design of prior art, the bushings and, accordingly, the conductors connected thereto are arranged in parallel in a horizontal row. Inside the encapsulation there is more space for the conductors in the vertical direction than in the horizontal direction. This has to do with certain other restrictions regarding the switchgear design that need not be further described in this context. According to prior art, the conductors are tubular with a circular outer periphery, which is generally a perfect design in order to promote conductivity as well as to prevent the upcoming of discharges and short circuits. However, for the described switchgear design, the applicant has realised that this conductor design is insufficient for optimising the conducting and voltage-carrying functionality of the conductors and at the same time minimizing the risk of having electric discharges or short circuits between individual conductors or between conductors and surrounding walls. The applicant has also realised that this problem is not only connected to switchgear but to electric power distribution arrangements in general in which there are more restricted space in a first direction than in a second direction cross wise to the longitudinal direction of an electric conductor arranged therein.
It is an object of the present invention to present an electric power distribution arrangement as initially defined, the design of which is such that the risk of having electric discharges or short circuits between individual conductors or between conductors and surrounding walls is reduced or minimized.